System of synchronizing signaling apparatus



Feb. 28, 1928.

A. L. MATTE SYSTEM OF SYNCHRONIZING SIGNALING APPARATUS Original FiledFeb. 26, 1925 INVENTOR. fllfliatze Patented Feb. 28 1928.

UNITED STATES PATENT OFFICE.

ANDREW L. MATTE, OE S UMMIT, NEW JERSEY, ASSIGNOR TO AMERICAN TELEIHON'BAND TELEGRAPH COMPANY, A CORPORATION 01' NEW YORK.

SYSTEM OF SYNGHRONIZING SIGNALING APPARATUS.

Original application filed February 26, 1925, Serial No. 11,801. Dividedand this application filed Hay l, 1927. Serial No. 193,893.

An object of my invention is to provide a new and improved system ofsynchronizing apparatus at points between which an electricaltransmission is effected. Another object of my invention is to providefor proper synchronous relation of the currents in the various parts ofan electric signaling sys tem. Another object is to provide forsynchronizing by currents of suitable fre- 19 quency, more particularlyto synchronlze relatively low frequency apparatus by trans mission ofhigher frequency currents. Still another object is to govern thefrequency of a vacuum tube oscillator by impressing a current ofharmonic frequency thereon.

These and various other objects of my'invention will become apparent onconsideration of an embodiment of the invention which I have chosen forillustration and 10 which I now present by way of example in thefollowing specification taken with the accompanying drawing. It will beunderstood that the invention is defined in the appended claims and thatthe following dell scription relates more particularly to the exampleshown in the drawing.

The drawing is a diagram showing two stations East and West with two-waytransmission between them.

At station West there is a vacuum tube oscillation generator 0 whichdelivers current of a certain fundamental frequency to the distorter orharmonic generator H, from which a composite current with thefundamental and harmonics goes to the phase splitter N I refer to thesefundamental and harmonics as components.

The phase splitter N comprising "the condenser 14 and resistance 15splits each of these simple components into two phases 90 apart,impressing the corresponding electromotive forces across the filamentand grid of the respective vacuum tubes 16 and 17. Since these tubesdraw substantially no current from the input circuits, there will besubstantially-no reaction on the phase splitter, and the output currentsfrom the vacuum tubes 16 and 17 will be in the proper 90 relation forthe two components of each of the component frequencies, the fundamentaland the odd harmonics.

The output currents from the vacuum tubes 16 and 17 go to respectiveattenuation equalizers E which bring the different frequency componentsto a desired intensity relation. From there the currents go torespective amplifiers A and are put on the respective conductor pairs 18and 19 to which hand filters BF are connected in multiple. Each bandfilter BF passes only one of the harmonic frequencies.

Each harmonic component passed by a respective band filter goes to aresective sending network SN controlled by a rey or equivalent device.The signal wave trains from each sending net SN go through a respectiveband filter SF and thence in mul tiple to the common conductor pair 20and to the line W It will be seen that the various carrier currents onthe line W differ not only in frequency, being all harmonics of a singlefundamental, but that for each frequency there are two components 90apart in,

phase, one componet put on through the con ductors 18 and the otherthrough the conductors 19. All these component currents are modified toform signals by means of the sending networks SN except that onecomponent in one phase is appropriated for securing synchronism at thestation East; the other phase of the same frequency is suppressed. Theone component current appropriated for synchronizing is put through theconductor pair 13 to the input of a band filter BF, and its output goeson the line W along with the modulated signaling currents.

At the station East the currents received from the line W go through theconductors 23 to respective band filters RF which pass the respectivefrequencies. These currents then go through suitable phase adjusters PEto the respective detectors D and D whose output currents control thereceiving polar relays R and R The detectors D and D also receive currents of the same frequency but a quarter phase apart over theconductors 27 and 28 from a source that will he pointed out presently.One of these locally generated bun rents corresponds in phase with onephase of signal current, and the other locally generated currentcorresponds in phase with the other phase of signal current, andtherefore, one phase of signal current is detected I relation arerequired These are supplied over the respective circuits27 and 28, and"priated for synchronizing and'sent through in one detector D and theother in'detector D,,. For these detectors D and D local currents of thesame frequency as the'respective carrier currents and in proper phasetheir generation inthe proper phase relation will now be'described.

v The particular harmonic frequency approthe conductors 43 at stationWest may thought of ashaving the frequency nd where d is the fundamentalfrequency and n is an integral multiplier. At the receiving stal5 tionthis particular harmonic will be passed f application of the harmonicfrequency nd to.

through an appropriate band filter BF and over the conductors labelledml to the input ofthe vacuum tube oscillator 46. The natural frequencyof. this oscillator 46 is, as

nearly as practicable, adjusted. to be equal to (Z, Whereas the inputfrequency is ad. The

' the input of this oscillator adjusted rather alrea closely to thenatural-frequency d, forces frequency (1.

The output from the oscillator 46 goes through the transformer 47 to theharmonic generator or distorter H. The output-from the said oscillatorto operate at precisely the the harmonic generator H- goes to the appa-.

responds to that indicated as Y, and already described in detail.

This application is a division of my application Serial No. 11,801,filed February 26, 1925, and renewed at or shortly before the time offiling the present application.

I claim:

1. The method of synchronizing a relatively low frequency vacuum tubeoscillator at a distance by transmitting and applying thereto a currentof harmonic frequency,

2. The method of synchronizing two vacuum.tube-oscillators ofapproximately the same relatively low natural frequency, which consistsin derivinga harmonic'current from one of said oscillators andtransmitting it and applying it "to the other of said oscillators. a

3. In a communication system, comprising a relatively low frequencyvacuum tube oscillator at the sending end and a similar oscillator ofapproximately the same natural frequency at the receiving end, themethod of synchronizing them which consists in transmitting a current ofharmonic frequency and applying it to the oscillator at the receivingend and thereby forcing it into synchronism at the said relatively lowfrequency. a

4. In a system comprising two widely separated vacuum tube oscillatorsnaturally tuned nearly together, the method of forcing one of them tothe frequency of the other which consists in transmitting from sai otheroscillator a current of harmonic frequency and applying it to the said"one oscillator.

In testimony whereof, I have signed my name to this specification this19th day of May 1927. a 4

ANDREW L. MATTE."

